Relief valve



R. S. HEISE RELIEF VALVE May 3, 1932.

Filed July 5,v 1928 Patented May 3, 1932 Uma 'res noscoE s. nEIsn E DAYTON. onIo RELIEF VALVE Application filed .uly 5,

This invention relates to relief valves and the like, and is particularly adapted to be used in connection with electric ovens where pressure developing within the oven, due to the formation of steam, requires that it be released, and where later, upon cooling of the oven, condensation of steam within the oven causes a vacuum which also must be relieved to prevent damage tothe oven.

rlhese and other objects, as will hereinafter appear, are accomplished by this invention which is fully described in thefollowing specification and shown in the `accompanying drawings, in which- Figure 1 is a longitudinal section through a pressure valve embodying the invention and showing the valve in the normal or inoperative position;

Fig. 2 is a similar view showing the valve pressed outwardly by steam or gas pressure within the oven;

Fig. 3 is a section on the line 3 3 of Fig. 1;

Fig. 4 is a section on the line 4-4 of Fig. 2; and

Fig. 5 is an end view showing Vthe outer end of the valve cap.

The embodiment illustrated comprises a valve body 01 barrel 10 having an opening'` forming a longitudinal chamber 11 which is preferably cylindrical in form and which is machined to receive a piston 12 vslidably, mounted therein. The inner end ofthe barrel 10 is partially 'closed and is provided with an extension 13 which is smaller so as to form a shoulder 14 thereon, the extension 18 being screw-threaded to receive a nut 15. The nut 15 and extension 13 are provided with openings 15- and 13a respectively. The outer end of the barrel 10 is also screw-threaded to accommodate a threaded cap 16. The cap lo is provided with vent holes 16EL so as to permit free movement of the piston 12, as will herein-V after be described. 4

The piston 12 is provided with depressions 17 and 18 at its two ends which are adapted Y The operation ofthe valve islas follows:

1s2s.` serial No. 290,316.'

to receive springs 19 and 2O which arein compression with the opposite ends bearing upon theY inner end .of vthe barrel 10 and the inner surface of thecap 16. These springs hold each other mutually incompression so that when thevalve is notracted upon by any outside force, the piston 12 assumes anormal intermediate position as shown in Fig. 1.

The piston12 isprovided with an annular groove 21 whichcommum'cates with the def pression -17 through a series oftransverse passages 22k anda longitudinal opening23. The barrel 10 is providedwith` a series of openings 24 (see Fig. 4) which are adapted to register'with the groove 21 when the piston 12 is moved outwardly to the positionshown in Fig.,y 2. A similar set of openings 25. is also provided which are adapted to be placed incommunication with the groove 21 when the piston is forced back in the opposite direction as will later be described. i n' This pressure-operated valve yis especially adapted tobe usedy as a relief valve for ovens, particularly electric ovens, tireless cookers and the like. `When so used, the Areduced l yportion l13Vof the barrelis passed through a suitableopening in the sheet metal lining 26 of the oven A which is surrounded usually'by a sheet metal housing B. I have provided a cuplilre member C whichext'ends through an opening D in the housing B.- The member C tightly'surrounds the barrel 10 and is secured thereon' by means of a ring E Vwhich tightly surrounds lthe barrel 10 and is frictiona-lly held thereon. v

The ovenA is tightly sealed previous to being heated so that when steam4 pressure is generated therein, `it is necessary. to provide means for relieving it.. This pressure acting upon the pistonk 12 will force it from the normal position shown in Fig.I 1 tothe operativeposition shown in Fig. 2, in which the groove21 is brou ht into registration` with the kopenings'24. ressure thus be relieved, steam from the oven A passing through the openings 23 and 22 and the groove 2l to the openings 24 and thence to the atmosphere.

Much of the air previously contained in the oven A will mix With the steam and Will pass out to the atmosphere in this manner so that as long as the steam'pressure is mainta-ined Within the oven A, the ovenWill be filled principally with steam. When, therefore, the generation of steam ceases, and the oven is permitted tov cool oil, this steam Will condense landa vacuum Willthus .be produced Within the oven A. When this happens, the valve Will act in a reverse direction to relieve the vacuum thus produced. Thisis accomplished by the pressure of the atmosphere Which is now greater than the pressure Within the oven, forcing the piston l2 back so -as to compress the spring 19 until the groove 2liin .thepiston`12.isfbrought into registration 4withithe'openings 25. When this ocours, a leak 'of air therethrough into the groove ;21an'd thence through the passages 22 and 23 occurs which 4eventually brings Aan equalization of `pressure Within the .oven A With that :of the Vatmosphere surrounding saine. y n

W'hile Ihave shown and described but a single embodiment `or myinvention, it is to bevnnderstood'iithat it islcapableof many modiiicat-ions, Ghanges, Itherefore, inthe constructioni-aiid arrangement maybe made which .do Snot depart fii'roin vthe spirit and scope=--of1the :invention Las covered by the -appended fclainis. 'Ic'laimz il. A :relie-f 'valvecomprising .a barrel, a piston 'slidablethereiin a spring on each side oflsaidlpistonjtending 'to lmaintainit in a neutral position, passageslinfthe piston and barrel ywhich fare normally. 4out of `registration 'With. eachother Wlienthepistonfis in the neutralv'position but may be brought into cate with a closed vessel, a channel in said piston between the periphery thereof and the side adjacent said vessel, said chamber being provided With openings to the atmosphere on either side of the normal position of said channel and adapted to register there- With'ivhen the piston is displaced a predetermined amount in either direction.

In testimony whereof, I have hereunto set my hand and aliXed my seal this 15th day of June, 1928.

ROSCOE S. HEI'SE.

registration When said piston is moved in either directionby- Vpressure'iirom said neui tralpositionsoasto permit gas on either'side ofthepvalve to passthe valve.

2. yA relieiivalve comprising 1a barrel, a piston slidable therein, a-spring on each side of lsafi'd piston tending vto maintain rit in a neutral position, a passage in said piston, a plurality oipassages in said'barrel either of which is adaptedfy to register with said passage in piston when the piston is moveda pre-V 'Y determined distance, said passages being out` of registrati-on'vvhen the' pistonl is in the neutral" position. A

i3; 'A-reliefvalve coi'nprisinga chamber, a

60' pistoneslidable'therein, yieldable means actl ing-upon said/,piston tendingt-o maintain saine 4at ,an intermediate point thereof vand oppose movement ineither direction, one Aend of said chamber being :open to the atmos: phere, Vthe 'otherbeing adapted to Y communi- 

